Jump to content

Waterproofing an Ammo Can

Lounge Fly
Followers 2

Recommended Posts

I want to make a time capsule that I can bury underground. This is NOT a geocache, it's for personal interest. I've looked many places for some ways to waterproof an ammo can, but can't really find anything anywhere. I figured I'd ask the genius engineering geocaching community (not sarcasm) if there are any ways to make sure that moisture wouldn't get through an ammo can's seal.

I've looked through a number of similar posts on here. I keep seeing PVC pipe as an alternative, but there are some things that i want to place in it that I would prefer not to bend, and may not fit properly in a circular container.


Thanks for any and all help!

Link to comment

I've known ammo cans to spend s significant time under water, and not leak!

Now, spending a long time (years?) under ground, might overcome the seal, but as MartyBartfast said, the container will rust, and that will probably happen before the seal would rot.

IMO, His advice is good about the plastic ammo boxes.


Another container to consider might be one of the larger Starfrit Lock & Lock containers. I bolded the brand name because there are imitators out there that aren't as strong, and don't seal as good.


There are some of those containers that will hold as much or more than an ammo box, and maybe even a better size format.

Link to comment

True ammo cans were designed to keep things (mostly ammo) dry and serviceable for lengthy periods of time. They were not however, intended to be permanently submersed nor buried in-ground for long term storage, as individual units.


Constant and direct water and/or soil contact provides electrolytes which aid in destructive rust-through.


You can use a (steel) ammo can -- not one of the plastic wannabe ammo cans -- along with strong to moderate protection from water or soil contact. To bury it, simply encase it in a easy-to-build wooden coffin. If in a high and dry area, not a problem. The contents should remain intact for 30-40-50 years and longer. If buried in waterlogged soil, you are gonna have to do a bit more.


A new-ish product, Liquid EPDM Rubber® could well be your solution. Painted inside and out of the 'coffin'. This stuff is not cheap!

Link to comment

If you are going to have a time capsule in place for a long time, I suggest encasing a container in concrete.

Or use large diameter pvc piping from Lowes, etc. The joints get sealed for pipe use and remain watertight indefinitely. Seal the pipe (e.g., 8 inches diameter) with the connecting cement (it's a glue, not concrete), & it will have to be sawed open decades from now to find the "buried treasure."

Link to comment

Sorry for the lateness in my reply

Thanks all for your suggestions. I had been a little concerned about rust affecting an ammo can over a prolonged period of time, and you guys helped confirm that. i thought I read somewhere that there was a rubber you could basically paint on, which was brought to light here too, but alas, it's quite expensive.


I've also thought about pelican cases, but not sure where to get them...at least a real one and not a knock off brand.


I'll take a look at the starfrit lock and lock. Never heard of it. Thanks for that suggestion!


Also, I had already looked at real time capsules online. Both of the links supplied here and a few others I've already seen. The problem is, either they're too expensive (like that chrome one), they're too small for what I want to put in, or they're too childish.


Thanks again everyone for all your suggestions! I knew the GC community would know where to turn :)

Link to comment

I build time capsules. I have done containment experiments since I was a kid, and have been making them ever since.


There are several issues which need to be addressed, all vital to your goals.


And the first of which is, what is your goal? Is it something that you want to dig up later in life, a personal "then and now"? Are you wanting others to find it? if so, then just anybody, a select group like friends or family, or a specific "kind" of person, such as an archaeologist, historian, or other professional?


What kind of items are being stored? If by your description they cannot be bent or fit in a circular container, then are we talking artwork, books, phonograph records, or photographs? What materials are they made of? There are many materials that while they can be protected from moisture & oxygen, they may be inherently unstable, such as older photographic materials, wood-pulp & acid-processed paper, leather, natural glues & adhesives, latex, and some plastics, especially the soft, flexible ones, like soft vinyl. Anything with an odor is very questionable as a candidate for long-term storage.


All liquids are bad candidates, avoid them. If they are truly essential for the purpose of the capsule, then they will require very special, space-hogging packaging.


How large does your container need to be? Generally, the larger the container, the deeper it will need to be buried for the same level of muggle resistance in the same time frame.


Are you able to purge & seal a container with argon or nitrogen?


What are the ground conditions? Will it be several meters of stable soil, with bedrock not far down? Will it be wooded or barren, firm soil or loose sand? Does it swing from deluge to drought? Is it acid, alkaline, or saline? If you are digging by hand shovel, will it be yielding, or loaded with tree roots & rocks? Is it far out to where you would want camping gear & an auxiliary fuel tank, or is it within a stone's throw of encroaching developments?


And how long will it need to be there until found? Are you looking at a few years, a few decades, generations, centuries, millennia, or the deeper times?


How much in time, materials, money, and other resources can you devote to it? Do you have any particular craft skills, such as modelmaking, moldmaking, plumbing, carpentry, machining, ceramics, sculpting, or even candlemaking? All of these skills and more can be of immense value in assembling a reliable time capsule package that is both doable and affordable.


I have checked all of the pre-made time capsule suppliers that I could find, including the Amalco and the Future Packaging options. In my reckoning, none of the containers but the heaviest FP's are satisfactory beyond a few centuries, and outside of the above two, most are nothing but mild steel biscuit tins with fancy labels & papers, literally no different than Altoids or Danish butter cookie tins. Even the few stainless steel cans are made the same way, with unsealed seams that will drain out a water-filled canister in a matter of minutes.


You would do infinitely better with an Igloo jug.


In any case, there are other options from scrapyards, military surplus, and repurposed industrial materials and items that can do a better job at a lower cost. The US military has, or had, ammo can style containers that are much better for burial than the more familiar steel ammo cans. There are missile and mortar cases, made of 1/8 inch thick aluminum with stainless steel latches and synthetic rubber seals, that are better than the aluminum Amalco tubes, hold much more, and cost a lot less. Conversely, there are also similar ones with regular steel latches, or some with some parts stainless, some parts regular steel.


You will need to examine them in person, to determine if they are proper candidates for the job. Bring a good ferrite magnet. Nothing with external regular-steel parts, no matter how well painted, coated, or plated, is suitable for long-term burial & recovery.


Pelican cases are available at sporting goods stores, camera & musical instruments stores, and other places. They range from cellphone cases to gaffer trunks. They are a very good case, probably the best that is available to the general consumer. Their stainless steel hingepins should hold up well, though if I used them for time capsules, I would personally replace them with titanium ones. If you live in or visit the Los Angeles area, they are headquartered in Torrance, north of the Torrance Airport (nearest geocache, "Gavin's Special Day No. 2" (GC4H899).


Check their website.


The US military has similar cases, some even made by Pelican. If you can find them, you can get them for much less than the Pelican cases in the store, and even their non-Pelican ones are good, as long as they do not use regular steel pins, screws, rivets, or other hardware. And as long as they have no structural or seal damage.


Non-Pelican marine-grade cases for boats may be another option. They should have only type 316 stainless, titanium, monel, or heavy brass hardware & fasteners. Look for these at boating supply or shipyards.


There's a lot more, but this post is already pretty bloated. If you can be more specific about your goals, materials, terrain, size, means, and other factors, a more concise, tailored, and relevant response can be made.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Followers 2
  • Create New...